Mobile in vivo camera robots provide visual feedback in surgery

Minimally invasive surgery offers patients less trauma, shorter recovery
times and less scarring. However, the small incisions used in these techniques,
such as laparoscopy, restrict surgeons’ views of the operating environment.
The cameras used in these procedures are generally large devices outside the patient’s
body, also limiting the views available to the surgeon.

Researchers at the University of Nebraska-Lincoln
and at the University of Nebraska Medical Center in Omaha are working on miniature
mobile camera-bearing robots that can be inserted into the body and that can provide
vision assistance without being confined to the entry site.
These prototype mini surgical robots are
equipped with cameras to give the surgeon an inside view during laparascopic procedures.
The larger of the three devices is an earlier prototype. Today’s versions
are smaller and have cameras that can pan and tilt.
They developed several types of in
vivo camera robots, including fixed-base and wheeled. The fixed-base devices can
pan and tilt, but do not move on their own. Instead, they are placed in various
locations by the surgeon.

The wheeled robot is 15 mm in diameter
and 75 mm long and has two helical wheels that are independently driven by DC motors,
allowing it to traverse abdominal organs. Its tail prevents it from spinning but
lets it reverse direction.

The scientists tested a wheeled robot
without a camera and found that, with a weight of 25 g, it has enough force to climb
the rough and hilly terrain of the abdomen. They also tested a wheeled mobile robot
with a camera, bringing the weight up to 50 g. The adjustable-focus video camera
is 20 mm in diameter and 100 mm in length. It also has a helical wheel and a stabilizing
tail. The camera’s tilt mechanism allows it to be tipped 15° without
changing the position of the wheels.

A surgical team inserted the mobile
adjustable-focus robotic camera (MARC) into an animal’s abdominal cavity through
a standard laparoscopic trocar, or tool port. The camera uses tiny image sensors
designed for commercial use in cell phones. The investigators found that the acquired
images are comparable to those provided by current laparoscopic systems.

The MARC explored regions within the
abdominal cavity, and the camera helped the surgeons focus on specific areas. They
removed a gallbladder, with the robotic camera providing the only visual feedback.
They found that the robot was extremely useful and gave them a better understanding
of the surgical environment than they would have had with a standard laparoscope.

The investigators are working to reduce
the robot to a size that fits in a traditional 15-mm laparoscopic trocar. Size reduction
is a challenge, according to Shane M. Farritor, associate professor of mechanical
engineering at the university. Some robots used in testing were tethered, so another
important goal is to make the robots wireless and to incorporate additional sensors
that may be able to give diagnostic and other feedback. He said that the researchers
want to move toward robots that can cut, pull, push — all the things that
surgeons do.

Someday there may even be miniature
robots designed for specific surgical tasks, and multiple robots may be sent
into the body to do a variety of tasks simultaneously.